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Tunnel regarded as one of the safest


TUNNEL ENGINEERS contacted by NCE this week agreed that the St Gotthard tunnel should have been among the safest in the Alps.

They also agreed that operators would have to consider imposing restrictions on tunnel access, because its sophisticated fire safety systems failed to save lives.

Last week's fire showed that more needed to be done to help motorists escape within minutes of a blaze starting.

Like the Mont Blanc fire in 1999, most people in the St Gotthard blaze are thought to have died within minutes of the fire starting.

Unlike the 36 year old Mont Blanc tunnel, where safety flaws were exposed in the 1999 fire, St Gotthard had more sophisticated safety management, fire detection and fire response systems.

It was equipped with a state of the art 25,000kW capacity ventilation system when opened to traffic in 1980.

The Swiss tunnel also incorporates a parallel service tunnel that serves as an escape route. This tunnel is pressurised and connected to the road tunnel every 250m. Signs next to the carriageway direct motorists to the nearest entry point.

The St Gotthard tunnel also has four ventilation shafts along its 16km length, to allow clean air in and through which exhaust fumes are expelled.

This contrasts with the 11.6km Mont Blanc tunnel which was only ventilated from each end and had no parallel escape tunnel.

In addition, motorists using the St Gotthard tunnel are handed leaflets explaining what they should do if fire breaks out in the tunnel.

St Gotthard tunnel operators can monitor traffic on closed circuit television and can stop motorists entering the tunnel if any of the 715 fire sensors in the running tunnel warn that a fire has broken out.

These fire sensors trigger alarms if temperatures rise faster than 5infinityC per minute.

Another fire alarm is also triggered if the temperature inside the tunnel exceeds 58infinityC.

When a fire alarm is activated, emergency lighting comes on and small emergency vehicles can reach the blaze by squeezing down the emergency access path next to the road.

Emergency services at both ends of the tunnel are also primed for rapid response.

Andrew Bolton

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